土壤病毒的研究进展与挑战

A Review of Researches on Viruses in Soil–Advancement and Challenges

病毒是由蛋白质和核酸组成的结构简单的非细胞型生物实体,全球病毒数量估算为4.80Í1031,远高于具有细胞型结构的生物数量。土壤是病毒重要的储藏库,土壤中病毒主要以侵染原核生物的噬菌体为主,其数量与寄主细胞数目和土壤理化指标密切相关。虽然学术界已意识到土壤病毒在调控微生物群落结构组成、影响土壤元素循环利用、促进生物进化、以及影响动植物病害,乃至人类健康等方面可能起到重要的作用,但由于受到土壤病毒颗粒的吸附性、土壤异质性,以及研究手段和分析平台的制约,我们对土壤病毒的认知和重视程度远落后于流动的海洋等水体环境。土壤病毒宏基因组中大量的基因序列无法判断其来源及功能,被划分为未知基因,所以病毒也被喻为生物“暗物质”和最大的未知基因宝库。本文在简要介绍了病毒的形态,在土壤中数量、存在形式和多样性的基础上,着重介绍了利用分子标记基因、RAPD和宏病毒组研究技术解析土壤病毒多样性的方法及其局限性,阐述土壤病毒已证实和潜在生态功能。最后,文章提出未来土壤病毒研究应加强的研究方向,强调土壤病毒与土壤微生物耦合研究在揭示土壤生态功能研究中的重要性。

Viruses are non-cellular biological entities,simple in structure,composed of proteins outside and nucleic acids inside.The total number of virus-like particles(VLPs)in the Earth biosphere was estimated about 4.80Í1031,which is overwhelmingly higher than that of organisms with cellular structure therein.Soil is an important reservoir of viruses,consisting mainly of bacteriophages(phages)that are able to infect prokaryotes.Metadata analysis shows that the number of the viruses in soil is closely related to the number of their host cells and certain soil physical and chemical properties.Although researchers in this aspect have realized that the viruses in soil may play an important role in regulating composition of soil microbial communities,thus influencing recycling of soil elements,promoting microbial evolution,and affecting the health of animals and plants,as well as human beings.However,due to high adsorbability of the soil virus particles and heterogeneity of the soil,as well as the limitation of research methods and analysis platforms,the cognition of and the attention paid to the viruses in soil in the current researches lags far behind those in the environments of flowing waterbodies,like river,oceans,etc.Among the soil viral metagenomes,a huge number of genes remain undetermined in sequence,source and function and hence are sorted into the catalogue of unknown genes.Consequently,viruses in soil are deemed as biological‘dark matter’and the largest unexploited gene treasure trove.In this paper,a brief introduction to morphology,abundance,existing form and diversity of the viruses in soil,a review of the methods and their limitations in using molecular marker genes,random amplified polymorphic DNA-PCR and metagenomic analysis techniques to parse diversity of the viruses in soil,and then discussions about validated and potential ecological functions of the viruses were presented.In the end,directions of the researches in future on viruses in soil that should be strengthened were brought forth,stressing the importance of coupling studies on soil viruses and soil microorganisms in future studies to reveal ecological functions of the soil.